It is well-known to support a television set on a wall bracket. In hospitals, for example, it is also known to provide an extendible linkage which has a fixed end mounted to the wall, and which has a movable end carrying a bracket. The linkage is comprised of parallel links, so the bracket is maintained in a constant attitude with respect to the wall as the bracket is moved about. The bracket, in turn, carries a television set, monitor, or other article, which may be pushed and pulled with respect to the wall by persons desiring a convenient setting; such setting may, of course, include simply moving the television out of the way when not in use. In order to provide great flexibility in setting, the article is connected to the bracket by at least a rotary joint which permits the article to be rotated about a vertical axis as the linkage is moved. Often a universal joint is also employed to permit omnidirectional tilting of the article with respect to the floor. It is known, for example, to provide a Hooke or Cardan joint, featuring crossed pins, to provide tilting motion about a vertical, rotary axis. The Hooke joint tends to be quite complex.
It is also known to provide a ball and socket joint, where a ball member is conveniently formed on a rotary member; the mating spherical socket is snuggly attached to the ball member and affixed to the supported article. Thus, the rotary member provides for rotation of the article about a vertical axis, with respect to a wall support linkage, and the ball and socket joint provides for omnidirectional tilt. In the support of an electrically powered article such as a television set, it is desirable to conceal electrical wires by feeding them from a wall source, through the central enclosure of the linkage, and, finally, down through a vertical hole in the rotary member and ball member, and into the television cabinet. This creates an aesthetic look to the wall-mounted arrangement. Rotation of the rotary member is limited to approximately 360 degrees, by stops. One difficulty which may be experienced in the use of the described ball and socket joint is that, although the rotary member strikes a stop, the socket may be forced to rotate still further about the ball member. If the television and socket are forced to rotate a full 360 degrees beyond the rotary member stop, and possibly further, the wires could twist and break.
The invention now to be described obviates the problem inherent in the prior ball and socket joints for supporting an article.